Clamping member for tipless cord connectors



E. s. M LARN 2,419,652

CLAMPING MEMBER FOR TIPLESS CORD CONNECTORS April 29, 1947.

Filed Feb. 22, 1943 INVENTOR.

ATTORNEY Patented Apr. .29, 1947 CLAMPIfi G MEMBER FOR TIPLESS CORD CONNECTORS Ernest s. Mcliarn, Manhasset, N. ,Y., assignor to International Standard Electric Corporation, New York, N, Y., a corporation of Delaware 2 I Application February 2;, 1194:, Serial No. 476,737

6 Claims; (01. 173-340) This invention relates to a clamping member for tipless cord connectors and is a continuation in part of co-pending application Serial No.

450,027, filed July 7, 1942, issued as Patent 2,312,970 on March 2, 1943.

The present invention has for its object the provision of an improved clamping member for use with the telephone cord connector disclosed in the above-mentioned application.

Another object of the invention is to provide a clamping member of simplified construction I which may be molded by automatic machinery from a plastic substance.

Still another object of the invention is the provision of a novel arrangement by which pronged contact members may be inserted in the clamping member or removed therefrom.

. Other objects will appear in the following description given with the aid of the accompanying drawings, of which Fig. 1 shows a plan view of a clamping member according to the invention as it appears positioned in a. telephone cord connector of the kind disclosed in the above-mentioned application;

Fig. 2 is a section taken through 22 of Fig. 1;

Fig. 3 is a section taken through 3-3 of Fig. 1;

Fig. 4 shows on an enlarged scale a detail of the clamping member partly in section. with the pronged contact members removed, the portion in section being similar to that shown in Fig. 3;

Fig. 5 shows a detail of the clamping member partly in section with the pronged contact members removed. The section of the member is similar to that shown in Fig. 2 but on a considerably larger scale;

Figs. 6 and 7 show in perspective pronged contact members according to the present invention.

' members are used which may be replaced when the teeth become worn or corroded thus reduc- Th invention is shown considerably enlarged in all of the drawings for the sake of clearness.

In the application referred to above, a telephone cord connector is disclosed by which cords of a known kind provided with connecting lugs may be connected to a telephone sub-set. The connector may be used also to connect the socalled tipless cords-bymeans of a clamping member which is provided with contact members having insulation piercing teeth or prongs which when an end of the tipless cord is placed in a recess provided therefor in theconnector underneath the clamping member, the latter may be pressed down on the cord by screws which pass through openings in the clamping member to cause the clamping member to secure the cord in the recess and at the same time the insulation piercing prongs of the contact members are pressed through the cord insulation and make contact with the respective conductors therein. The screws in addition to their function of exerting pressure on the clamping member make connection between the contact members and telephone subset circuits. I

The present invention contemplates a clamping j member having an initially lower cost than the one described in the above mentioned patent application, the molding process being simplified because no metal partsare inserted during the molding operation. Removable metal contact ing the replacement costs of the device. vThe latter feature is important in some tropical countries where climatic conditions cause most metals to corrode quickly. I

Th present invention isparticularly adapted for use with the base member of a telephone cord connector shown together with the present invention in Figs. 2 and 3 in which reference character I 0 indicates a portion of a base of a telephone instrument made of .molded insulating material. Near one edge, the base is formed with a raised portion II to provide an area of increased thickmess; The part I.l in'the present embodiment is triangular in shape and near each corner thereof is -a hollow-threaded bushing I2 formed with a lug l3 extending below the under surface of the base to which appropriate subset circuits are con-.

nected. The threaded members are seti in the base during the molding process.

A recess [4 is formed in part ll of the base for the purpose of receiving th insulated end section of a length of telephone cord I5 which may be of the kind described in applicant's Patents No. 2,226,733 and No. 2,226,734, both issued on December 31, 1940. The outer part of recess 14 has a depending section l6 which.cooperates with a complementary part 56 formed on a clamping member according to the present invention, now about to be described. A When untipped cord is to be used, a clamping member 50 of novel construction is provided for gripping the cord and retaining it in position in the recess as well as establishing connections between the cord conductors and bushings I2.

Clamping member 50 as shown in the drawings,

- tary slanting surface, preferably corrugated, to

provide an effective g ip on the wire in the recess. ,The clamping member in the present embodiment has three spaced contact members I, 2 and 3 preferably of a non-corrosive metal detachably held in slots molded in member 56 which will now be I described. Y

At each of the opposite ends of a cavity 60 in.

the under surface of member 50 a pair of spaced ridges is formed, of which, ridges 6| and 62 shown -lationship .to eachother, a detachable contac member disposed in each slot, insulation piercing points on the respective contact members proiecting beyond the surface of said clamping mem- On the'upper surface of member 50 between i adjacent slots, fins 4 are formed as shown in the various figures to provide increased surface insu lation between the contact members.

Referring to Figures 2 and 5, reference characters 65 and 66 indicate small recesses formed in the base of the slots between the respective ridges 6| to 64; whichrecesses are for the purpose of holding small projections 61 and 68 formed on the edges of the contact members I, 2 and 3 to retain the contact members securely in the respective slots.

In the present invention the contact memberscomprise a flat section 69 adapted to fit into the slots just described, the flat section being stamped out to'form a plurality of separate tines, the lower part of the tines being formed into insulation piercing prongs and an upper part 10 integral with the fiat section provided with an eyelet turned over to register with one of the openings for screws 52 to' 54 in the clamping member.

By means of the arrangement just described the contact members are disposed in. spaced relation to each other in the slots of the clamping member so that theinsulation piercing prongs of the tines project below the, under surface of the ridge formed in the clamping member and each set of prongs are aligned over a conductor of the parallel conductor cord disposed in recess M, the prongs and the depending ridgebeing so proportioned that when screws 52 to 54 are tightened, the cord is clamped securely between the under surface 51 of ridge 55 and recess I, the prongs penetrating the insulation of the cord and extending into the conductors thereof.

'As shown in Figure 2 the contact members I,

her, a screw individua1 to each contact member for holding said clamping member in engagement with a. parallel conductor cord and for forcing the points of said contact members through the insulation of a conductor, means "for automati-.

cally locking said contact members in said slots in the act of their insertion, said screws comprising-means for'connecting circuits to said contact members.-.

2. A device according to claim 1 in which said means for automatically locking said contact members in said slots comprise projections formed on the respective contact members which engage individual retaining means therefor formed in said clamping member.

3. A device according to claim 1 in which said means for automatically locking said contact members in said slots comprise projections formed on the respective contact members which enter recesses formed in said clamping member when said contact members have been inserted a predetermined distance into said slots.

' 4. A device according to claim 1 in which each contact member comprises a flat portion'adapted 2 or 3 closely fit their respective slots while the projections 61 and 68 extend respectively into recesses 65 and 66 formed in the edges of the respective slots, the flat upper surface of the projections engaging the upper surface of the recesses holding the contacts in position. The under surface of the projections are slightly rounded while the upper part of the slot is tapered. By this arrangement when the contact member is inserted into the slot and pressure is exerted thereon the tapered portion ,of the slot engages the curved under part of the projections and cams the tines of the contact member towards each other permitting the contact member clamping member provided with a plurality of slots disposed side to side in spaced parallel re- .to. said contact members.

to be enclosed within one of said slots, the greater part of the area of said flat portion being formed into a plurality of tines, and an insulation piercing prong formed at the end of each tine projecting beyond said slot.

5. A device according to claim 1 in which each contact member comprises a flat portion adapted to be enclosed within one of said slots, the greater part of the width of said flat portion being formed into a plurality of tines, a projecting member formed at the edge of at least one of said tines I been inserted a. predetermined distance into said slot.

6. In a device of the character described, a clamping member including a plurality of spaced, parallel slots centrally located in said member and registering with parallel wires of a conductor cord, a detachable contact member in each slot having prongs proportioned to pierce. the insula tion of said conductor cord, means for automatically locking said detachable contact members in their respective slots. an insulating fin between .said parallel slots adapted to insulate successive contact members at the upper surface of said clamping member'and a screw for each contact 'member for holding said clamping member in cord-piercing position and for connecting circuits ERNEST s. McLARN.

REFERENCES CITED The following references are of record in the file' of this patent:

UNITED I STATES PATENTS Number Name Date 1,685,420 Higham Sept. 25, 1928 2,022,486 Blakeslee Nov. 26, 1930 1,747,896 Gates Feb. 18, 1930 2,312,970 McLarn Mar. 2, 1943 

